1. Field of the Invention
The present invention pertains to the art of gas appliances and, more particularly, to a switching device, incorporated in an overall gas flow control valve assembly, for activating an igniter for the flow of gas.
2. Discussion of the Prior Art
In a gas appliance, such as a range, it is common to provide a plurality of gas burner elements to which gas is supplied through respective flow control valves. Typically, each valve is provided with a knob which is exposed at the front of the appliance and can be rotated to regulate the flow of gas to a respective burner. In years past, a pilot light was provided to ignite the regulated flow of gas. In order to avoid the need to maintain a constantly lit pilot light, it has now become commonplace to provide an electric ignition system for the gas, with the ignition system including an electrode provided at the burner element and an electric switch controlled by movement of the knob to develop a series of sparks at the electrode. In general, when the knob is rotated, an initial high gas flow/ignition position is reached wherein a cam inside the switch causes contacts to become electrically engaged. Once the gas is ignited, the user can rotate the knob further to terminate the sparking operation and to establish a desired flame setting.
With this arrangement, it is possible for the user of the appliance to release the knob while still in the initial position such that the igniter continues to unnecessarily spark. This circumstance is considered disadvantageous from various standpoints, including operational and economic inefficiencies. In addition, it would be advantageous to be able to initiate a sparking operation with the control knob in various rotational locations instead of only at an initial, rotational position.
Based on the above, there exists a need in the art for a valve and igniter switch assembly which is designed to automatically cease a sparking operation whenever an associated control knob is released. In addition, there exists a need for a valve and igniter switch assembly which will enable a user to initiate a sparking operation without requiring the knob to be in a specific operational position.
The present invention is directed to a gas flow control and igniter switching assembly for a gas appliance including a rotary valve body from which projects a control stem along an axially extending axis, with the stem being both rotatable about the axis to control a flow rate of gas through the valve and, preferably, shiftable in the axial direction relative to the valve body. In accordance with the most preferred embodiment of the invention, the switch portion of the assembly includes first and second contacts which become electrically engaged with each other upon shifting of the stem in the axial direction, substantially independent of the rotary angular position of the stem relative to the valve body.
In accordance with a preferred embodiment of the invention, the switch portion of the assembly includes an outer casing formed from first and second pieces which are snap-fittingly interconnected. The first and second contacts are seated in respective portions of the first casing piece. Interposed between the casing pieces is an activation member which is generally in the form of a disk. Attached to the activation member is an electrical connector which, in the most preferred form of the invention, is constituted by a spring member that abuts the first casing piece and biases the activation member towards the second casing piece. The first and second casing pieces, as well as the activation member, are provided with respective holes through which the stem passes. The hole in the first casing piece actually extends about a sleeve projecting from the valve body in order to non-rotatably mount the first casing piece to the valve body, while the stem is frictionally held in the bore of the activation member. A control knob is attached to the end of the stem for selectively rotating and axially shifting the stem.
With this arrangement, the activation member shifts axially in unison with the stem and relative to the contact members. Depressing the knob causes the activation member to electrically interconnect the contacts to initiate a sparking operation for igniting a supply of gas flowing through the valve. Since the activation member is biased away from the first casing piece and the contacts, releasing the control knob will automatically cause the electrical connector to become spaced from the contacts to terminate the sparking operation. The particular configuration of the contacts and the electrical connector establishes a wide range of angular positions for the knob in which the sparking will occur upon depression of the stem. In the most preferred form of the invention, the sparking can be activated throughout substantially the entire range of rotation of the stem.
Additional objects, features and advantages of the invention will become more fully apparent from the following detailed description of a preferred embodiment when taken in conjunction with the drawings wherein like reference numerals refer to corresponding parts in the several views.